The potential of gas plasma technology for targeting breast cancer

Despite therapeutic improvements in recent years, breast cancer remains an often fatal disease. In addition, breast cancer ulceration may occur during late stages, further complicating therapeutic or palliative interventions. In the past decade, a novel technology received significant attention in the medical field: gas plasma. This topical treatment relies on the partial ionization of gases that simultaneously produce a plethora of reactive oxygen and nitrogen species (ROS/RNS). Such local ROS/RNS overload inactivates tumour cells in a non-necrotic manner and was recently identified to induce immunogenic cancer cell death (ICD). ICD promotes dendritic cell maturation and amplifies antitumour immunity capable of targeting breast cancer metastases. Gas plasma technology was also shown to provide additive toxicity in combination with radio and chemotherapy and re-sensitized drug-resistant breast cancer cells. This work outlines the assets of gas plasma technology as a novel tool for targeting breast cancer by summarizing the action of plasma devices, the roles of ROS, signalling pathways, modes of cell death, combination therapies and immunological consequences of gas plasma exposure in breast cancer cells in vitro, in vivo, and in patient-derived microtissues ex vivo.

ROS Pleiotropy in Melanoma and Local Therapy with Physical Modalities

Metabolic energy production naturally generates unwanted products such as reactive oxygen species (ROS), causing oxidative damage. Oxidative damage has been linked to several pathologies, including diabetes, premature aging, neurodegenerative diseases, and cancer. ROS were therefore originally anticipated as an imperative evil, a product of an imperfect system. More recently, however, the role of ROS in signaling and tumor treatment is increasingly acknowledged. This review addresses the main types, sources, and pathways of ROS in melanoma by linking their pleiotropic roles in antioxidant and oxidant regulation, hypoxia, metabolism, and cell death. In addition, the implications of ROS in various physical therapy modalities targeting melanoma, such as radiotherapy, electrochemotherapy, hyperthermia, photodynamic therapy, and medical gas plasma, are also discussed. By including ROS in the main picture of melanoma skin cancer and as an integral part of cancer therapies, a greater understanding of melanoma cell biology is presented, which ultimately may elucidate additional clues on targeting therapy resistance of this most deadly form of skin cancer.

Antitumor Effects in Gas Plasma-Treated Patient-Derived Microtissues—An Adjuvant Therapy for Ulcerating Breast Cancer?

Despite global research and continuous improvement in therapy, cancer remains a challenging disease globally, substantiating the need for new treatment avenues. Medical gas plasma technology has emerged as a promising approach in oncology in the last years. Several investigations have provided evidence of an antitumor action in vitro and in vivo, including our recent work on plasma-mediated reduction of breast cancer in mice. However, studies of gas plasma exposure on patient-derived tumors with their distinct microenvironment (TME) are scarce. To this end, we here investigated patient-derived breast cancer tissue after gas plasma-treated ex vivo. The tissues were disjoint to pieces smaller than 100 µm, embedded in collagen, and incubated for several days. The viability of the breast cancer tissue clusters and their outgrowth into their gel microenvironment declined with plasma treatment. This was associated with caspase 3-dependent apoptotic cell death, paralleled by an increased expression of the anti-metastatic adhesion molecule epithelial (E)-cadherin. Multiplex chemokine/cytokine analysis revealed a marked decline in the release of the interleukins 6 and 8 (IL-6, IL-8) and monocyte-chemoattractant-protein 1 (MCP) known to promote a cancer-promoting milieu in the TME. In summary, we provide here, for the first time, evidence of a beneficial activity of gas plasma exposure on human patient-derived breast cancer tissue.